F-Theta Laser Beam Shaping for Zero-Taper Machining
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Laser machining systems face challenges in achieving zero and negative taper cuts due to limitations in beam profile uniformity and divergence, requiring expensive precision CNC machines and complex control systems.
Innovation Solution
A method and system utilizing a laser beam with a top-hat profile and narrow beam divergence, directed through an F-theta lens with a long focal length, allowing for controlled beam tilt angles and reduced taper angles by converting Gaussian beams into top-hat beams for precise machining.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional laser beam with Gaussian profile and wide divergence is used, then the laser machining system is simple, but the beam profile uniformity is poor and taper control is difficult
Solution Approach 1:
The patent changes the beam profile parameter from Gaussian to top-hat distribution and reduces beam divergence angle from wide to narrow (less than 3 degrees), which directly improves taper control and edge quality in laser machining
Solution Approach 2:
The patent introduces an F-theta lens with long focal length (greater than 250mm) as an intermediary optical element to achieve narrow beam divergence and uniform top-hat profile, avoiding the need for complex precision CNC positioning systems
2Manufacturing precision
If a special trepanning head with fixed tilt angle is used, then zero taper cuts can be achieved, but the system is complex and only suitable for small hole drilling
Solution Approach 1:
The patent creates a universal laser beam delivery system using F-theta lens that can perform both small hole drilling and large area machining with zero or negative taper, replacing specialized trepanning heads with a versatile optical solution
3Manufacturing precision
If high precision CNC stage with 4-5 axis is used, then zero taper cut can be achieved, but the equipment cost and control complexity increase significantly
Solution Approach 1:
The patent replaces complex mechanical precision positioning systems (4-5 axis CNC stages) with an optical solution using F-theta lens and top-hat beam profile, achieving zero taper cuts through optical means rather than mechanical positioning
4Loss of energy
If conventional laser beam with wide divergence is used, then the system is simple, but power loss occurs during machining
Solution Approach 1:
The patent reduces beam divergence angle to less than 3 degrees through the F-theta lens optical system, which maintains beam intensity and reduces power loss during laser machining operations
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables the production of zero or negative taper cuts with reduced power loss and lower equipment costs, suitable for various materials like ceramic matrix composites, and allows for more precise control over machined features.
Implementation Method 1
directing, from an F-theta lens having a long focal length of greater than about 250 millimeters, a laser beam at a non-perpendicular beam tilt angle from an optical axis of the lens
Implementation Method 2
narrow beam divergence angle of between about 1 degree and about 3 degrees
Implementation Method 3
The impingement of the laser beam on the workpiece locally melts and/or vaporizes the workpiece material to produce or extend a hole or cut in the workpiece
Implementation Method 4
locally melts and/or vaporizes the workpiece material
Implementation Method 5
locally melts and/or vaporizes the workpiece material
Data Source
AI summary
A laser machining method includes directing, from an F-theta lens having a long focal length of greater than about 250 millimeters, a laser beam at a non-perpendicular beam tilt angle from an optical axis of the lens having a top-hat profile and a narrow beam divergence angle of between about 1 degree and about 3 degrees towards a workpiece on a stage movable in at least an X-direction and a Y-direction, engaging the directed laser beam with the workpiece disposed in the usable field of view, moving the workpiece and the directed laser beam relative to each other, and removing portions of the workpiece with the directed laser beam to define a machined surface.